Biomechanics of weightlifting: The effect of morphology on lifting technique in the deadlift and other resistance Exercises

Body types of athletes vary greatly depending on the sport they compete in, thus when designing resistance exercise programs it is essential to take into consideration the morphology of the athlete. This enables the coach to adjust the technique of the exercise (e.g. deadlifting) accordingly (Delavier, 2010). According to Hales, (2010) maximizing the deadlift is extremely important for enhancing strength and power of athletes in a variety of sports, focusing on sports with high demands on strengthening trunk extensors, knees and hips. Bezerra et al., (2013) described a dead lift stating it consisted of the lifter’s knees being flexed in a squat-like position, elbows extended using an alternating handgrip to grip the bar positioned under the lifter’s feet. During the concentric exercise movement, the bar is raised from the floor to a mid-thigh position by extending the hip and knee joints (Bezerra et al., 2013). From this it has been identified that due to athletes having a unique morphological shape, especially in sports teams, musculosketal system joint levers have to be taken into consideration when applying technique to deadlifting because muscles are worked differently in short limbed people compared to long limbed people (e.g. centre player in basketball compared to point guard) (Swinton et al., 2011). Long limbed people are more capable of performing deadlift with correct technique and lifting heavier weights because of having the ability to have the legs slightly bent allowing the quadriceps to push the body upwards with greater force (Beggs, 2011). Whereas short limbed athletes have to rely more on upper body strength to lift the bar, therefore losing upward force (Beggs, 2011). Due to the biomechanics of the body of long limbed, short torso athletes the favoured technique of executing the deadlift is partially bent legs with a forward tilt allowing them to lift heavy weights, activating mainly the quadriceps muscles. Delavier, (2010) stated that the morphology of the athlete depends a great deal on the muscles activated in other resistance training such as the squat. For example short limbed athletes are notoriously better at performing the squat correctly, activating the quadriceps muscles, thus developing that muscle group. However, if a long limbed athlete executed the same squat, different muscles would be activated due to the length of the femurs with tension being put on the hamstrings gracilis muscles by trying to prevent the forward lean of the torso. Therefore when long limbed athletes squat the muscles that are predominantly developed are the gleuteals and lumbar muscles and in order to focus on quadriceps activation, weight must be added, risking safety of the athlete if their technique is not correct (Delavier, 2010). Therefore, many factors such as the arrangement of muscle fibres in the rectus femoris (bipennate) along with the muscle length and the joint angle contribute to the correct successful deadlift technique being performed (Baechle and Earle , 2008). For example, Gorsuch et al., (2013) researched the effect of squat depth on multiarticular muscle activation in collegiate cross-country runners comparing male and female athletes. Using surface electromyography muscle activation of the rectus femoris, biceps femoris, lumbar erector spinae, and gastrocnemius was recorded during partial and parallel squats and it was discovered that differences were found because of different ranges of movement at the hip. However this study had a small sample size so would not be easily transferable to wider populations, yet the findings could be used for further research (Gorsuch et al., 2013). The arrangement of muscle fibres within the lifter also affects the technique used when deadlifting because of the angle of pennation of the muscle (Burke, 1981). For example Hales et al., (2009) stated that even though an athlete has a certain muscle length muscle ﬁbre composition the athlete can incorporate different lifting styles to enhance their biomechanical characteristics. Supporting this Hales, (2010) identified that an athlete with long torso and short arms and short arms and short torso, when struggling with the conventional deadlift technique might find the sumo deadlift technique effective and easier for their particular morphology. The Sumo Deadlift consists of the feet pointing outward resulting in a ‘larger mediolateral (shear) ground force component compared with the conventional style deadlift’ (Hales, 2010:47). However despite this there are still similar biomechanical issues with lifting, especially at maximal load, therefore depending on an athlete’s biomechanical characteristics such as limb length and arm span, different approaches may be undertaken such as the leg lift, back lift or modified back lift (Hales, 2010). Subject to the morphology of the lifter, the angle of pennation (increasing when muscle shortens) could differ, effecting strength and velocity of the lift (Baechle and Earle , 2008; Favre and Peterson, 2012). A variety of muscle groups are used, however the deadlift targets posterior muscles, undergoing dynamic and isometric movement such as the lower back (extensor spinae), quadriceps, hamstrings and gluteus maximus (Brechue and Abe, 2002). According to Chulvi-Medrano et al., (2010) muscle length and joint angle is also a factor of biomechanics of the body that contributes to the effects of morphology on lifting technique in the deadlift. Supporting this Delavier, (2010) stated that flexibility of the ankles greatly affected the ability preform a correct and effective squat, for example poor flexibility could result in tilting the torso and putting strain on posterior muscles of thigh. In conclusion there are many factors of morphology that affect the technique of deadlifting. People who look like they have muscles of the same size, due to differing factors such as the arrangement of muscle fibres, the muscle length, joint angle and recruitment of muscular activation unique morphology of the lifter can affect the technique adopted for deadlifting (Chulvi-Medrano et al., 2010). Within a team setting the strength and conditioning coach must assess the different biomechanical types and when lifting maximal load to increase strength and power, use the most suitable lift for that body type. For example leg lift, back lift or modified back lift, sumo squats are less encouraged as it has less dynamic correspondence to real life applications (Hales, 2010). Future recommendation is to improve player’s ankle flexibility to avoid tears before lifting maximal loads (Delavier, 2010). Reference list: Baechle, T.R. and Earle , R.W. (2008) Essentials of strength training and conditioning. (3rd ed.) United States : Human Kinetics . Beggs, L. (2011) comparison of muscle activation and kinematics during the deadlift using a double‐pronated and overhand/underhand grip. Unpublished Masters Theses, Kentucky: University of Kentucky. Bezerra, E.S., Simão, R., Fleck, S.J., Paz, G., Maia, M. and Costa, P.B. (2013) Electromyographic Activity of Lower Body Muscles during the Deadlift and Still-Legged Deadlift. Journal of Exercise Physiologyonline. Vol. 16, No. 3: 30-39. [Online] Available from: http://web.b.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=0e4a725f-3790-4719-8740-a592aa5ad379%40sessionmgr110&vid=6&hid=127 [accessed 17 April 2014] Brechue, W.F. and Abe, T. (2002) European Journal of Applied Physiology. The role of FFM accumulation and skeletal muscle architecture in powerlifting performance. Vol. 86, No. 4: 327-336. Burke, E.J. (1981) Toward an Understanding of Human Performance. (2nd ed.) NY: Mouvement Pubns. Chulvi-Medrano, I., García-Massó, X., Colado, J.C. and Pablos, C. (2010) Deadlift Muscle Force and Activation Under Stable and Unstable Conditions. Journal of Strength & Conditioning Research. Vol. 24, No. 10: 2723-2730. Delavier, F. (2010) Strength Training Anatomy. (3rd ed.) United states : Human Kinetics . Favre, M. and Peterson, M. (2012) Teaching the First Pull. Strength & Conditioning Journal. Vol. 34, No. 6: p 77–81. Gorsuch, J., Long, J., Miller, K., Primeau, K., and Rutledge, S. (2013) The Effect of Squat Depth on Multiarticular Muscle Activation in Collegiate Cross-Country Runners. Journal of Strength & Conditioning Research. Vol. 27, No. 9: 2619–2625. Hales, M., Johnson B., and Johnson J. (2009) Kinematic analysis of the powerlifting style squat and the conventional deadlift during competition: is there a cross-over effect between lifts? Journal of Strength and Conditioning Research. Vol. 23, No.9: 2574–2580. Swinton, P., Stewart, A., Keogh, J., Agouris, I. and Lloyd, L. (2011) Kinematic and Kinetic Analysis of Maximal Velocity Deadlifts Performed With and Without the Inclusion of Chain Resistance. Journal of Strength & Conditioning Research. Vol. 25, No. 11: 3163-3174.